[PATCH] Fix CDDCE miscompilation (PR tree-optimization/55018)

[Jakub Jelinek]

On Thu, Nov 01, 2012 at 09:26:25PM +0100, Hans-Peter Nilsson wrote:
> > Attached patch was bootstrapped&tested on
> 
> gcc/
> 	PR tree-optimization/55018
> 	* basic-block.h (dfs_find_deadend): New prototype.
> 	* cfganal.c (dfs_find_deadend): No longer static.  Use bitmap
> 	instead of sbitmap for visited.
> 	(flow_dfs_compute_reverse_execute): Use dfs_find_deadend here, too.
> 	* dominance.c (calc_dfs_tree): If saw_unconnected,
> 	traverse from dfs_find_deadend of unconnected b
> 	instead of b directly.
> 
> It seems this caused PR55168, ICE.

As Honza said, it was likely latent, and furthermore seems to be related to
the flow_dfs_compute_reverse_execute change from Steven (mentioning it
primarily what should we consider backporting if anything to release
branches).

	Jakub